Ground controllers were able to send commands to the Mars
Exploration Rover Spirit early Wednesday and received a
simple signal acknowledging that the rover heard them, but
they did not receive expected scientific and engineering
data during scheduled communication passes during the rest
of that martian day.

Project managers have not yet determined the cause, but
similar events occurred several times during the Mars
Pathfinder mission. The team is examining a number of
different scenarios, some of which would be resolved when
the rover wakes up after powering down at the end of the
martian day (around midday Pacific time Wednesday).

The next opportunity to hear from the vehicle is when the
rover may attempt to communicate with the Mars Global
Surveyor orbiter at about 8:30 p.m. Pacific time tonight. A
second communication opportunity may occur about two hours
later during a relay pass via the Mars Odyssey orbiter. If
necessary, the flight team will take additional recovery
steps early Thursday morning (the morning of sol 19 on Mars)
when the rover wakes up and can communicate directly with
Earth.

Full details on the rover's status will be described in the
next daily news conference Thursday at 9 a.m. Pacific time
at the Jet Propulsion Laboratory, which will be broadcast
live on NASA Television.